ZCZC MIATCPEP4 ALL TTAA00 KNHC DDHHMM BULLETIN Hurricane Hilary Advisory Number 16 NWS National Hurricane Center Miami FL EP092023 200 AM PDT Sun Aug 20 2023 ...HEAVY RAINS CONTINUE SPREADING NORTHWARD OVER THE BAJA PENINSULA AND THE SOUTHWESTERN UNITED STATES... ...CATASTROPHIC AND LIFE-THREATENING FLOODING LIKELY... SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...27.4N 115.0W ABOUT 30 MI...45 KM SSE OF PUNTA EUGENIA MEXICO ABOUT 385 MI...625 KM SSE OF SAN DIEGO CALIFORNIA MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H PRESENT MOVEMENT...NNW OR 345 DEGREES AT 21 MPH...33 KM/H MINIMUM CENTRAL PRESSURE...974 MB...28.77 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of Mexico has discontinued the Tropical Storm Warning for the west coast of the Baja California peninsula south of Santa Fe, and discontinued the Tropical Storm Warning for the east coast of the Baja California peninsula south of San Evaristo. The government of Mexico has discontinued the Tropical Storm Watch for the coast of mainland Mexico from Huatabampito to Guaymas. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for... * Baja California peninsula from Punta Abreojos to Cabo San Quintin A Hurricane Watch is in effect for... * Baja California peninsula north of Cabo San Quintin to Ensenada A Tropical Storm Warning is in effect for... * Baja California peninsula west coast from Punta Abreojos to Santa Fe * Baja California peninsula east coast from San Evaristo northward * Baja California peninsula north of Cabo San Quintin to the California/Mexico border * Mainland Mexico north of Guaymas * California/Mexico border to Point Mugu * Catalina Island A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A Hurricane Watch means that hurricane conditions are possible within the watch area, in this case within the next 12 to 24 hours. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning. Interests elsewhere in the southwestern U.S. should monitor the progress of Hilary. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 200 AM PDT (0900 UTC), the center of Hurricane Hilary was located near latitude 27.4 North, longitude 115.0 West. The hurricane is moving toward the north-northwest near 21 mph (33 km/h). Hilary is expected to accelerate as it moves north-northwestward to northward during the next day or two. On the forecast track, the center of Hilary will move close to the west-central coast of the Baja California Peninsula during the next few hours, and then move across southern California this afternoon. Maximum sustained winds are near 85 mph (140 km/h) with higher gusts. Weakening is expected, but Hilary is likely to still be a hurricane while it passes near the west coast of the central Baja California Peninsula this morning. Hilary is expected to weaken to a tropical storm before it reaches southern California. Hurricane-force winds extend outward up to 45 miles (75 km) from the center and tropical-storm-force winds extend outward up to 230 miles (370 km). A sustained wind of 44 mph (71 km/h) and a gust of 67 mph (108 km/h) were recently reported at Isla Cedros, Mexico. The estimated minimum central pressure is 974 mb (28.77 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Hilary can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDEP4 and WMO header WTPZ44 KNHC and on the web at hurricanes.gov/text/MIATCDEP4.shtml. RAINFALL: Hilary is expected to produce storm total rainfall amounts of 3 to 6 inches, with isolated maximum amounts up to 10 inches, across portions of the northern Baja California Peninsula through tonight. Flash and urban flooding, locally catastrophic, is expected, especially in the northern portions of the peninsula. Heavy rainfall in association with Hilary is expected across the Southwestern United States, most intense from today into Monday morning. Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 inches, are expected across portions of southern California and southern Nevada. Dangerous to catastrophic flooding is expected. Across portions of Oregon and Idaho, rainfall totals of 1 to 3 inches with local maxima to 5 inches are expected through Tuesday morning, resulting in localized, some significant, flash flooding. WIND: Hurricane conditions are expected within the hurricane warning area this morning and are possible within the hurricane watch area later today. Tropical storm conditions are occurring within the southern portion of the tropical storm warning area and will spread northward today. Tropical storm conditions are expected to begin in southern California later today. Winds could be particularly strong and gusty in and near areas of elevated terrain. Higher gusts are expected well inland and will persist even after the system becomes post-tropical. STORM SURGE: A dangerous storm surge is likely to produce coastal flooding along the western Baja California peninsula of Mexico near where the center passes the coast in areas of onshore winds, or east of the center if Hilary makes landfall. The surge will be accompanied by large and destructive waves. Coastal flooding is possible along the northern coast of the Gulf of California today through early Monday. TORNADOES: A tornado or two may occur today from mid-morning through the evening over parts of the lower Colorado River Valley, Mojave Desert, and Imperial Valley regions. SURF: Large swells generated by Hilary will affect portions of the Baja California Peninsula and southern California over the next couple of days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 500 AM PDT. Next complete advisory at 800 AM PDT. $$ Forecaster Pasch NNNN